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Old 13th January 2010, 10:23 AM   #11
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However, Henk-Jan, how did you get them delivered to the Hollandlands
Henk-Jan is an importer of the CSS products.

http://www.juoiga.nl/
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Old 26th January 2010, 12:52 AM   #12
Mark Kravchenko --- www.kravchenko-audio.com
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I simulated a pair in a 55l vented box as a comparison. It would be worth building it as a baseline to compare in listening tests to any new "exotic" design: TRIO8 "Unhorn" Proof Of Concept - Home Theater Systems - Electronics and Forum - HomeTheaterShack
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I'm waiting for Mark to send me the cabinets he's designed for a pair of TRIO8s and then we'll likely make a special series of kits available.

The cold weather and Mark's empolyment have slowed things sown a little.
Hi guys
Since I've had the pleasure of reading your posts and the joy of fooling around long enough to design an interesting box I'll post a few thoughts.

Bob is right things have slowed down a bit to much. But I'm getting back on track by tomorrow. Bills wait for no man ! There will be some activity very soon.

Peter has had a point made that we all agree on. A direct comparison could be instructive against the Unhorn design and a standard vented box. I'll build a box with a slotted port. I will round the external opening to a 1" radius and that should take care of any potential turbulence. But as simulated in Hornresp there is no real great difference in SPL. There is a slightly better edge close to the low end cutoff compared to a vented box as modeled by Bjorno in the tapped horn for car thread. He made a very convincing case for his discussion. Hornresp and other modeling programs are refined enough to negate any arguement of what a conventional box will accomplish once is jumps from a computer model to the real world. I have LSPcad, LEAP, Bass Box, WinISD and few others that are spreadsheet based. They all agree when you factor in the method of modeling that they use to generate the SPL curves. That is one reason I do a head to head comparison of a design in Hornresp. Apples to Apples.

But to be pointed there is no difference is the direct frontal sound created by two TRIO8's in a vented box or an UNHORN enclosure. There is no great increase in efficiency if the cabinet is not corner loaded. When twi TRIO8's are loaded into an UNHORN enclosure the drivers are between 1 and 2 db more efficient than the same setup in a vented enclosure. That is a small enough difference to make it a measurement anomaly.

What is is:

If you enjoy the clean sound of an open baffle sub-woofer you get clean and clear sound with the efficiency of a vented enclosure. There is no smoke and mirrors. It uses the same drivers with no real horn loading. The loading technique in the enclosure is to short to create any acoustical step-up transformer effect that you would get from a real horn.

Again you get a sound of an open baffle without the losses in efficiency that an open baffles has. When the box is corner loaded you get the inherent efficiency gains that any box will attain when there are greater paths of reflection. The plus is that the UNHORN enclosure is designed to work very well with this type of loading. You do not get the tubby bass that seems to come from the standard vented box placed in a corner. It sounds more natural and actually horn like or again like an open baffle. But with almost 12 db greater efficiency when corner loaded that is balanced over the boxes pass band not centered around where a port and woofer mutually couple in a corner. As measured in a corner we had on average 96 db/watt with less than 3 db fluctuation with measurements taken every 5 hz. Pretty flat for corner loading.

What has been achieved is an interesting combination of tinkering and excellent drivers. A friend of mine and I had these two TRIO8 drivers pushing 124db in a 12' x 10' room. Our peak input power was 340 watts and the program material was Vierne's variations on Westminster chime's on Reference recordings. Tough on any subwoofer. We also tried Mussorgsky's Pictures at an Ehxibition by Jean Guillou on Dorian. Jaw dropping. This from two little 8 inch drivers.

So when there is all said and done you might try it. It will not be any worse than a conventional cabinet. And with it's inherent design tweeks it may be much better depending on the location you can put it in. I personally think it sounds better.

Mark
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Old 26th January 2010, 04:01 PM   #13
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Work gets in the way of all the fun things , if only the lottery guys would pull the right numbers! I'm in no hurry for a design ,good things come to those who wait. I'm sure it will be a great design.
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Old 27th January 2010, 01:56 AM   #14
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Originally Posted by mwmkravchenko View Post
But as simulated in Hornresp there is no real great difference in SPL. There is a slightly better edge close to the low end cutoff compared to a vented box as modeled by Bjorno in the tapped horn for car thread.
Bear in mind that HornResp assumes no losses (someone correct me if I'm wrong here, LOL). This is not the case with most of the programs that model vented enclosures. In the real world, the response peaks won't be as high as predicted by HornResp, and the response at the corners of the passband are likely to be a bit more "rounded", due to losses. Passband efficiency is also likely to be a little bit lower. This should be taken into consideration when comparing models.
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Old 30th January 2010, 12:46 PM   #15
Mark Kravchenko --- www.kravchenko-audio.com
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In the real world, the response peaks won't be as high as predicted by HornResp, and the response at the corners of the passband are likely to be a bit more "rounded", due to losses. Passband efficiency is also likely to be a little bit lower. This should be taken into consideration when comparing models.
Hi Brian

You had front row center seats in the other unhorn thread. I posted the simulated and measured results of the final design. They did in fact agree quite well with your sumation of rounding off more gradually on the low end and having little to no peaking. I did get in the real world 1 watt SPL not corner loaded slightly higher than your calculated 87.7 db. So I think I am in full agreement with your thoughts on the driver box combination's efficiency.

Tapped Horn For Car

Your comment back then:

Tapped Horn For Car

The box is still behaving. The only clarification I made was to post the average efficiency at 96 db/ watt in a corner position. Other than that the measurements are the same.

Mark
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Old 14th March 2010, 01:57 AM   #16
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Are there any plans or suggestions for a TRIO8 design, using a single driver, sealed or vented but not PR?
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Old 14th March 2010, 03:11 AM   #17
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Originally Posted by oodi View Post
Are there any plans or suggestions for a TRIO8 design, using a single driver, sealed or vented but not PR?
Not that I've seen, but it only takes a minute to model something up in Unibox or WinISD. Sealed is easy; a 13L net box gives a Qt of 0.7 and an F3 of 54Hz and only just exceeds Xmax below rated power below 30Hz.

Ported isn't quite as easy. 30L models a really nice box, but the get a low enough port air speed, the port becomes very long. This is why PR's are suggested.

The sims are for 12L sealed.
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File Type: gif CB Response CSS Trio 8.gif (21.2 KB, 227 views)
File Type: gif CB Excursion CSS Trio 8.gif (20.4 KB, 223 views)
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Old 14th March 2010, 03:15 AM   #18
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These are for 30L net ported with a 7.6cm (3") ID port 49.6cm (19.53") long. A slot port might be integrated into a relatively small box easily.
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File Type: gif VB Response CSS Trio 8.gif (23.3 KB, 219 views)
File Type: gif VB Excursion CSS Trio 8.gif (22.0 KB, 217 views)
File Type: gif VB PortAirSpeed CSS Trio 8.gif (22.2 KB, 219 views)
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Old 14th March 2010, 03:26 AM   #19
oodi is offline oodi  Canada
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Originally Posted by Brett View Post
The sims are for 12L sealed.
I have to admit, I know nothing about subwoofer design. I do have a book on speaker design I read a long time ago. But in the end, I much rather just build something that has been done before and promises to bring decent result.

Would a cube be just as good as a box of a different shape as long a 12L volume is maintained?

Does is matter which direction the driver is oriented? Could the the driver be facing the floor if the box had suitable legs?

Adi
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Old 14th March 2010, 03:40 AM   #20
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Originally Posted by oodi View Post
I have to admit, I know nothing about subwoofer design. I do have a book on speaker design I read a long time ago. But in the end, I much rather just build something that has been done before and promises to bring decent result.
Subs are easy. I already had the T/S loaded for this driver as I have a sketch of an idea to use 4/ch in a later design, if I ever get around to it. Fo sealed, I then told Unibox to give me a box with a Qt of 0.7 (max flat, max extension alignment) and hit the start button. They are handy programs to have when learning as you can quickly see the effects of changing something.

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Originally Posted by oodi View Post
Would a cube be just as good as a box of a different shape as long a 12L volume is maintained?
12L is the net internal volume, that is you need to add the volume taken by the driver and any internal bracing. However, it's not all that critical; 12L + 3L for driver + 1L for bracing. Bigger is fine if the dimensions work out better for you.
Shape isn't really important in most sub designs until the box volume of the dimensions of one side get large enough to have a resonance in the sub's passband. Not a problem for you here.

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Originally Posted by oodi View Post
Does is matter which direction the driver is oriented? Could the the driver be facing the floor if the box had suitable legs?

Adi
Unibox calcs a 0.98 which is fine for up/down firing. Keep the baffle >50mm from the floor and you should be fine.
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